1. Field of the Invention
This invention relates to a product, namely an improved sour-cream analog, as well as to a method for the preparation thereof. More specifically, the invention relates to a low-cost powdered product which can be stored on the shelf at room temperature, and which can be readily reconstituted by hand under counter-top conditions to yield a sour-cream-type product having excellent refrigerator-shelf stability. The powder is prepared by first spray-drying a low-fat, chemically "fermented" base slurry. A pre-gelatinized starch powder is blended into the spray-dried product, to both assist in the reconstitution/emulsification, and to enhance the stability of product after reconstitution.
2. Description of the Prior Art
In the past, sour cream, and sour-cream products such as dips and dressings, attained wide public favor.
Sour cream is a colloidal suspension, wherein a high-fat dairy emulsion is entrapped within a fluid protein-based coagulum. Natural sour cream has a butter-fat content of at least 18% by weight.
Natural sour cream was prepared by fermenting a dairy-base. The base was innoculated with bacteria, which caused a fermentation. As the fermentation proceeded, the acid slowly coagulated the protein in the dairy product to produce the smooth, viscous emulsion commonly recognized as sour cream.
Natural sour cream suffered, however, from a number of shortcomings.
The high-fat dairy base for sour cream was expensive. The natural fermentation process was a slow one.
Once "soured", sour cream had a limited shelf-stability, even under refrigeration. The limited shelf-life resulted from the continuing acid production by the coagulation-inducing bacteria. Even under refrigeration, the bacterial acid production continued. This limited the shelf-life for the soured product. As a result, the shelf-life of natural sour cream was typically not stable for more than about 14 days, after which whey began to exude from the coagulum.
To speed the coagulation, and to limit the continuing bacterial-acidification of the soured product, "artificial fermentation" processes were developed. The artificial fermentation consisted of adding an edible acid directly to the dairy base, under controlled conditions, to produce the desired coagulum without bacteriological action. Even artificially-fermented products were still limited to a maximum refrigerator shelf life to about two weeks before the coagulum-suspended emulsion "broke", with whey separating from the coagulum.
To gain long-term stability for a sour cream product, a number of sour-cream powders were developed. Some of these products, such as those disclosed in U.S. Pat. Nos. 3,357,838, and 3,090,688, were merely intended to be used as dry ingredients in processed foods. As such, they were not commonly regarded as products that could be reconstituted into a table-ready sour cream product. One sour-cream powder, as disclosed in U.S. Pat. No. 3,792,178, could be reconstituted, but remained stable for only a brief period. Another sour-cream powder, as disclosed in U.S. Pat. No. 3,443,960, incorporated a number of emulsifiers to permit the powder to be reconstituted with the aid of an electric mixer. The mixer provided sufficient energy-input so as to emulsify the powder/water blend. However, U.S. Pat. No. 3,443,960 did not purport to disclose a product, or teach a method, that would permit reconstitution of a sour cream powder with only hand effort.
A need continued to exist for a low-cost, product that was stable at room temperature, and that could be easily re-constituted to produce a viscous "sour cream" emulsion that exhibited excellent stability on the refrigerator shelf.